This means that after April 8, 2014, users running Windows XP Service Pack (SP) 3 -- the last service pack delivered for the 11-year-old operating system -- won't get any more updates. That includes both security and "non-security" hot fixes, free or paid support options and online technical content updates. And this also concerns support of MS Office 2003.

Despite that fact, Microsoft officials admit they know of customers who still won't have competed their migration off XP by that date. And some customers are still maintaining they won't migrate off XP until the hardware it is on fails, officials conceded.In the new Security Blog post, Tim Rains, Microsoft's Director of Trustworthy Computing threw in some new cautions about ignoring the April 8 XP support cut-off date.

Rains wrote that after April 8, "attackers will likely have more information about vulnerabilities in Windows XP than defenders." Microsoft's Security Response Center currently releases security updates for all affected products simultaneously, giving users an advantage over attackers, Rains said, reducing the time that attackers have to reverse engineer vulnerabilities.

Because a security update will never become available for XP after April 8, "Windows XP will essentially have a 'zero day' vulnerability forever," Rains noted.

Despite that fact, Microsoft officials have said they have no plans to extend yet again the cut-off date for support for XP. Currently (August 2013) Windows XP still had more than 37 percent desktop OS share. This is because all the next operating systems from Microsoft – Vista, Windows 7, and Windows 8 didn’t prove any advantages comparing with Windows XP.